Kinesin superfamily member 15 knockdown inhibits cell proliferation, migration, and invasion in nasopharyngeal carcinoma

Abstract

The aim of this study was to investigate the role of kinesin superfamily member 15 (KIF15) in nasopharyngeal carcinogenesis (NPC) and explore its underlying mechanisms. We employed various assays, including the CCK-8 assay, flow cytometry, the Transwell and scratch assay, Western blotting, and nude mice transplantation tumor, to investigate the impact of KIF15 on NPC. Our findings demonstrate that KIF15 plays a critical role in the proliferation, apoptosis, migration, and invasion of NPC cells. Furthermore, we discovered that silencing KIF15 inhibits cell proliferation, migration, and invasion while promoting apoptosis, and that KIF15's effect on NPC cell growth is mediated through the PI3K/AKT and P53 signaling pathways. Additionally, we showed that KIF15 promotes nasopharyngeal cancer cell growth in vivo. Our study sheds light on the significance of KIF15 in NPC by revealing that KIF15 knockdown inhibits NPC cell growth through the regulation of AKT-related signaling pathways. These findings suggest that KIF15 represents a promising therapeutic target for the prevention and treatment of NPC.

Keywords: Cell proliferation; Kinesins; Nasopharyngeal carcinoma.

Fig. 1. Expression of KIF15 in normal nasopharyngeal epithelial cells and NPC cell lines.

The mRNA (A) and protein (B) expression of KIF15 were detected in different cell lines (NP69, C666-1, CNE-2, SUNE-1, HONE-1, and 5-8F). Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma. *p < 0.05 vs. the NP69 group, n = 5.

Fig. 2. Effect of KIF15 knockdown on the proliferation of NPC cell lines.

The mRNA (A) and protein expression (C, D) of KIF15 were detected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines. The mRNA (B) and protein expression (C, E) of KIF15 were detected in KIF15-shRNA/5-8F and ScrshRNA/5-8F cell lines. The cell viability (F) and relative colony formation (stained with 0.5% crystal violet staining solution) (H, I) was detected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines. The cell viability (G) and relative colony formation (stained with 0.5% crystal violet staining solution) (J, K) was detected in KIF15-shRNA/5-8F and ScrshRNA/5-8F cell lines. Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma. **p < 0.01 vs. the shcontrol group, n = 5.

Fig. 3. KIF15 knockdown induces apoptosis in NPC cells.

(A, B) The flow cytometric analysis was detected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines. (C, D) The flow cytometric analysis was detected in KIF15-shRNA/5-8F and ScrshRNA/5-8F cell lines. The mRNA expression of Bax (E), Bcl-2 (G), and Bax/Bcl-2 (I) were detected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines. The mRNA expression of Bax (F), Bcl-2 (H), and Bax/Bcl-2 (J) were detected in KIF15-shRNA/5-8F and ScrshRNA/5-8F cell lines. The protein expression of cleaved-caspase 3 was detected in CNE-2 (K) and 5-8F (L) cells. Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma; ns, no significance. *p < 0.05 and **p < 0.01 vs. the shcontrol group, n = 5.

Fig. 4. Effect of KIF15 knockdown on migration and invasion of NPC cell lines.

Representative images of transwell-migration assays of CNE-2 (A) and 5-8F (B) cells and (C, D) quantification of cell migration expressed by cell counting. Representative images of scratch assay performed in CNE-2 (E) and 5-8F (F) cells. (G, H) The mobility (%) was measured 24 h after cells were scratched. Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma; transwell assays: stained with 0.1% crystal violet staining solution; original magnification ×200. *p < 0.05 and **p < 0.01 vs. the shcontrol group, n = 5.

Fig. 5. Effect of KIF15 knockdown on AKT and p53-dependent pathway of NPC cell lines.

(A) The protein expression of p-AKT, AKT (B), P53 (C), MMP2 (E), and MMP9 (G) were detected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines. (H) The protein expression of p-AKT, AKT (I), P53 (J), MMP2 (L), and MMP9 (N) were detected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines. The mRNA expression of MMP2 (D, F) and MMP9 (K, M) were detected. Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma. *p < 0.05 and **p < 0.01 vs. the shcontrol group, n = 5.

Fig. 6. KIF15 knockdown induces apoptosis in NPC cells through activation of p53.

CNE-2 (A) or 5-8F (B) cells were transfected with sip53 or negative control (NC) for 48 h, the mRNA expression of p53 was detected. KIF15-shRNA/CNE-2 (C, E) or KIF15-shRNA/5-8F (D, F) cells were transfected with sip53 or NC. The flow cytometric analysis was detected. The mRNA expression of bax (G, H), bcl-2 (I, J) and bax/bcl-2 (K, L) were detected. The protein expression of cleaved-caspase 3 was detected in CNE-2 (M) and 5-8F (N) cells. Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma. *p < 0.05 and **p < 0.01 vs. the KIF15-shRNA-NC group, n = 5.

Fig. 7. Effect of KIF15 knockdown on NPC cell growth in vivo.

(A, B) Mice and tumors in the different groups were shown. Tumor volume (C) and body weight (D) were recorded. (E, F) Representative in vivo images of luminescence shown in the livers of the live nude mouse was injected in KIF15-shRNA/CNE-2 and ScrshRNA/CNE-2 cell lines, respectively. Values are presented as mean ± SD. KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma. **p < 0.01 vs. the shcontrol group, n = 5.

Fig. 8. Molecular mechanism of KIF15 on NPC development.

KIF15, kinesin superfamily member 15; NPC, nasopharyngeal carcinoma.